And yet is still gaining registered voters.
All those dead DUmmies voting.
Early and often.
You beat me to it. I think you mean registered "Democratic" voters. And of course, don't forget the unregistered ones that still vote early and often. Again and again.
That actually would be theoretically possible - Say the Joneses and the Smiths move out (-4 adults, -4 children between them), and the Walkers, Browns, and Raymonds move in, all 3 of them are childless couples. That's 6 adults, 0 children. You've had a 25% decrease in population with a 50% increase in eligible voters.
Of course, this is Chicago, so even if that scenario occurred, I'd have to agree - you'd see a 150% increase in registered voters....